Core shaft clamping member



Oct. 4, 1966 F. R. ERBACH CORE SHAFT CLAMPING MEMBER Filed 00%;. 5, 1964 United States Patent 3,276,713 CORE SHAFT CLAMPING MEMBER Fred R. Erbach, Beloit, Wis., assignor to Beloit Corporation, Beloit, Wis., a corporation of Wisconsin Filed Oct. 5, 1964, Ser. No. 401,538 16 Claims. (Cl. 24268) The present. invention relates to improvements in winder shafts on which rolls of web material such as paper may be wound, and more particularly relates to an improved core shaft mechanism capable of supporting a hollow core for winding or unwinding a roll of web material.

In winding rolls of sheet or web material such as a continuous supply of paper in a papermaking machine, it is the general practice to provide a hollow tubular cylindrical core on which the paper is wound. Operations with the core require a shaft rotatably supported at its ends to support the core during winding or unwinding operations and the shaft must be capable of reliably gripping the core in a substantially coaxial position during the unwinding operation and to permit braking or driving of the shaft and a roll supported thereon during operation and stopping the shaft by braking thereof. The shaft also must be capable of quickly and easily gripping the core and releasing its grip on the core in order to allow the shaft to be removed from the core.

Various arrangements have been employed for the above purposes such as by employing an outer shell on the core shaft formed of metal sections arranged so that the outside circumference of the shell can be expanded or contracted. These constructions usually require complicated mechanical components expensive for manufacture and subject to wear. Other arrangements have utilized a flexible diaphragm for expanding the outer diameter of the core shaft although these constructions require the provision of air connections. These arrangements in many cases unduly prolong the operation of mounting the core on the shaft, and wherein they do not maintain good concentricity at higher speeds they cause undesirable variation in winding and unwinding tensions.

It is, therefore, an object of the present invention to provide a core shaft mechanism which is capable of rapidly receiving a tubular hollow core and rapidly gripping or releasing the core with a minimum of effort.

A further object of the invention is to provide a core shaft mechanism which is relatively inexpensive to manufacture and assemble, which includes a minimum of components and which is capable of long reliable wear without repair or adjustment.

A still further object of the invention is to provide an improved core shaft mechanism avoiding the necessity of providing a pneumatic or hydraulic equipment and which can easily and rapidly be operated to grip or to release a hollow core by an operator and which concentrically and reliably grips and supports a core with a wound roll thereon.

Many other features, advantages and additional objects of the present invention will become manifest to those versed in the art upon making reference to the detailed description which follows and the accompanying sheets of drawings in which preferred structural embodiments incorporating the principles of the present invention are shown by way of illustrative example only.

In the drawings:

FIGURE 1 is a schematic plan view of web winding and unwinding apparatus incorporating the principles of the present invention;

FIGURE 2 is a side elevational View of the apparatus of FIGURE 1;

FIGURE 3 is a fragmentary elevational view of a core shaft having mounted thereon a core clamping member 3,276,713 Patented Oct. 4, 1966 constructed in accordance with the principles of the present invention;

FIGURE 4 is an enlarged sectional view taken substantially along lines IVIV of FIGURE 3;

FIGURE 5 is an enlarged fragmentary sectional side view of a core and core clamping member mounted on a core shaft;

FIGURE 6 is a side elevational view of another embodiment of a resilient member employed in the invention; and

FIGURE 7 is a cross-sectional view of the embodiment of the resilient member shown in FIGURE 6.

As shown in the drawings:

Although the principles of the present invention are of utility in any core-shaft mechanism, a particularly useful application is made to core-shaft mounting arrangements in web forming and/or finishing apparatus and an illustrative embodiment herein shown consists of a shaftmounted core of a web windup reel or station in apparatus such as, for example, a paper making and/ or finishing machine or similar web forming or handling apparatus.

In the exemplary embodiment illustrated in FIGURES 1 and 2, a paper web indicated generally by the reference character W is shown on a paper making machine 10 traveling from a calender stack 11 to a windup reel 12 which receives the traveling web from the calendar stack and winds up a predetermined length of web thereon, after which the loaded reel is removed from the machine and replaced with an empty reel.

The calender stack 11 is more particularly characterized as comprising a large bottom roll 11a and a plurality of smaller rolls including rolls 11b and situated in vertical alignment with the bottom roll 11a. The paper web W emerges from the calender stack 11 on the off-running side of the nip defined by rolls 11a and 11b and extends under a guide roll 13 to a pressure or driving roll 14'. The web then enters the on-running side of the nip defined by the reel 12 and the roll 14 to be wound up in the manner of a coil on the reel 12.

The rolls Ila-11c of the calender stack 11 and the guide roll 13 are mounted for rotation on suitable mounting means. The pressure roll 14 is also mounted for rotation by suitable means which, in the illustrated embodiment, comprises a shaft 16 journaled for rotation on a pair of arms 17, 17. The arms 17, 17 are mounted for pivotal movement on blocks I8, 18 and the shaft 16 is connected to suitable motive or driving means such as an electric motor to provide rotation thereof.

In the illustrated arrangement wherein the traveling web is being wound up on the reel 12, the pressure roll 14 frictionally engages the reel 12 to drive or rotate the reel and as the diameter of the reel increases due to an increasing length of web being wound thereon the pressure roll 14 pivots correspondingly to maintain a satisfactory frictional or driving engagement with the periphery of the reel 12.

In winding up a reel of traveling web a thin-walled hollow core member indicated in the drawings at reference numeral 19 is slidably mounted on a rotatable shaft 20 for receiving the leading end of the web and for winding up the web thereon. After a predetermined length of web has been wound on the core, the core is removed from the shaft for transfer from the machine and is replaced on the shaft with an empty core for winding up another length of web.

The hollow core 19 may be constructed of inexpensive and perhaps expendable material such as, for example, a heavy paper board.

The utilization of such inexpensive material for the core, however, makes it desirable to fixedly connect the core to the shaft for co-rotation therewith during a winding and unwinding operation in order to prevent undue wear of the core.

In addition, it is desirable to axially align the core 19 on the shaft 20 with respect to any associated rolls such as, for example, the rolls 13 and 14 and the rolls of the calender stack 11 in the illustrated embodiment.

In accordance with the principles of the invention a pair of core-shaft clamping members 21, 21 are slidably adjustably mounted on the shaft 20 at opposite ends of the core 19 in order to positively axially position the core 19 with respect to the shaft 20 and to the associated rolls of the apparatus and to positively interconnect the core 19 and the shaft 20 for co-rotation therebetween.

It will be appreciated that during a winding or unwinding operation the shaft 20 is removably journaled for rotation in a pair of journal members as at 22, 22.

Referring to FIGURES 3-5, the diameter of an inner wall 23 of the core 19 is slightlyoversized with respect to the diameter of a peripheral wall 24 of the shaft 20 for easy yet snug sliding relation of the core on the shaft.

Each of the clamping members 2 1 is more particularly characterized as comprising an annular holding member 26 and a complemental nut or collar member 27. The holding member 26 is adapted to slide on the shaft 20 and to tightly abuttingly engage an end wall 28 of the core 19 to axially clamp the core, in cooperation with an associated holding member situated at the opposite end of the core, and to frictionally drive the core co-rotatably with the shaft 20.

For this purpose, the holding member 26 includes an annularly shaped body portion 29 having formed therethrou-gh a bore defined by a cylindrical side wall 30 for slidably receiving the shaft 20. A forward end wall 3-1 provides a radially extending shoulder or abutment for engaging the end wall 28 of the core 19 to prevent relative rotation between the holding member 26 and the core 19.

After the holding members 26 of the two clamping members 21, 21 have been slid on the shaft 20 and moved into tight abutting engagement with the end walls 28 of the core 19, the holding members are then locked on the shaft 20 to maintain such positioning and also to positively connect the holding members in fixed assembly with the shaft 20 to drive the core co-rotatably with the shaft.

Accordingly, the holding members 26 each comprise an axially extending sleeve portion 32 extending axially backwardly from the body portion 29 in radially spaced relation to the shaft 20. The configuration of the body and sleeve portion 29 and 32 is somewhat L-shaped, and the annular space between the sleeve portion 32 and the peripheral wall 24 of the shaft 20 constitutes a cavity or recess 33.

Housed within the cavity or chamber 33 are a plurality of annular members 34 which are centrally apertured to slide over the shaft 20. The inner diameters of the members 34 as defined by inner Walls 36 thereof are preferably just slightly greater than the diameter of the shaft 20, and the outer diameters of the members 34 as defined by outer walls 37 are preferably just slightly less than the outer diameter of the recess 33 as defined by an inner wall 38 of the holding member sleeve portion 32.

In the exemplary embodiment the annular members 34 each comprises a circumferentially continuous circularly shaped body portion 38 which is circular in cross-section and for reasons more apparent hereinafter the members 34 are preferably constituted of deform-able resilient material such as rubber, plastic or the like. By the phrase circular in cross-section is meant that a plane extending through the body portion of an annular member extending parallel to the axis of the annular member will reveal a circular cross-sectional view as shown in FIGURE 5.

In order to releasably lock the holding members 26 to the shaft 20 a centrally apertured annular insert or movable wall member 39 is carried in sliding relation on the shaft 20 and comprises an axially extending portion 40 and a radially outwardly extending portion 4 1 having a radial dimension which is slightly less than the radial dimension of the recess 33 such that the insert 39 is axially slidable on the shaft 20 within the recess 33. The radial portion 41 has formed thereon a radially extending wall or shoulder surface 42 adapted to abuttingly engage the resilient members 34 and to apply an axial force thereto.

It will be apparent that after the holding member 26, the resilient members 34 and the insert 39 of each of the clamping members 21 are slid into place on the shaft 20 and the holding members 26 are firmly pressed against the ends of the core 19 in a clamping action, any force tending to compress the resilient members 34 will tend to expand and to load such members in a radial direction. As a result, wall portions 43 of the resilient members which confront the peripheral wall 24 of the shaft 20 will firmly and tightly grippingly engage the shaft 20 and an opposite Wall portion 44 of the resilient members which confronts the inner wall 38 of the holding member 26 will grippingly engage the holding member to preclude relative rotation between the holding member 26 on the shaft 20.

In order to apply a suitable compressive force to the resilient members 34 the nut 27 is provided with a threaded axially extending inner wall 46 for receiving a complementarily threaded outer wall 47 of the holding member sleeve portion 32 to enable the nut to be axially and selectively adjustable with respect to the holding member 26. The nut 27 is provided with a radially extending wall 48 for abuttingly engaging an adjacent end Wall 49 of the insert 39. As the nut 27 is threaded on the holding member 26 a compressive force is applied to the resilient members 34 to load the resilient members radially against the peripheral wall 24 of the shaft 20 and the inner wall 38 of the holding member 26 to fixedly connect and grip the shaft 20 and the holding member 26 to prevent relative rotation and axial movement therebetween.

When such compressive force is applied to the resilient members 34 the members will deform from their free state configuration as illustrated in FIGURE 5 to a compressed state configuration which, depending on the magnitude of the compressive force applied, will tend to become more rectangularly shaped.

After such compressive force is released by threading the nut 27 in an opposite direction the resilient members 34 will tend to return from their com-pressed state configuration to their free state configuration, thereby releasing the loading effect between the holding member 26 and the shaft 20 and enabling the holding member to again rotate and move axially with respect to the shaft 20.

In order to ensure that the confronting wall portions 43 of the resilient members 34 will move away from the peripheral wall 24 of the shaft 20 upon release of the compressive force applied to the resilient members, a plurality of annularly shaped biasing members as at reference numeral 50 are mounted on the shaft 20 and interposed, respectively, between the resilient members 34 and between the shoulder surface 42 of the insert 39 and a wall surface 51 of the holding member 26 against which the endmost resilient members 34 are bottomed.

Each of the biasing members 50 is illustrated as comprising an axially split, annular spring member which is generally circular in cross-section having an inner diameter defined by an inner wall 54 which is slightly greater than the diameter of the peripheral wall 24 of the shaft 20. Accordingly, the spring members 50 are constructed such that when radially inwardly directed forces are applied thereto the members attain a compressed state configuration, whereby the inner diameters thereof are about equal to the diameter of the shaft 20. When such forces are released, however, the springs 50 will again expand to their free state configuration.

Referring again to FIGURE 5 it will be noted that the cross-sectional area of each of the spring members 50 is substantially less than the longitudinal cross-section of the resilient members 34 such that in an assembled condition the spring members abuttingly engage the confronting wall portion 43 of the resilient members to impart a radially outwardly directed bias to the resilient members when the nut 27 is released. Preferably the ratio of the diameters of the body portions of the resilient members 34 and the biasing members 50, as illustrated in FIGURE 5, is in the range of from about 6 to l to 2 to l, and in the illustrated embodiment this ratio is in the order of 4.3 to 1.

It will be appreciated that if the cross-sectional diameter of each of the spring members 50 is too great with respect to the diameter of the resilient members, the radially outwardly directed force applied to the resilient members by the spring members would be diminished since the spring members would engage the resilient members toward the center portions thereof. On the other hand, if the diameter of the spring members were too small the resilient members would tend to become embedded in the spring members.

As noted, in the embodiment of the invention illustrated in FIGURES 4 and 5 the resilient members 34 are circumferentially continuous and the spring members 50 are axially split, as best seen at reference numeral 45 in FIGURE 4.

In another embodiment illustrated in FIGURES 6 and 7 a spring member 50a having a circular longitudinal cross-section is actually positioned within a resilient member 3401 concentrically therewith, and both the spring 50a and the resilient member 34a are. axially split to provide interfacing radial Wall members 52 and 53. When the resilient member 50a is in a free state configuration, as shown in FIGURE 6, the inner diameter thereof as defined by inner wall 54a is just slightly greater than the diameter of the shaft 20.

As noted in FIGURE 3 the peripheral walls of the holding member 26 and the nut 27 of the clamping member 21 may be knurled in order to facilitate tightening and loosening of the clamping member. In addition, the radially innermost portions of the shoulder 42 of the insert 39 and the wall surface 51 of the holding member 26 are tapered as at 56 and 57 respectively to receive a portion of their respective spring members. In this manner the spring members are not depressed into their adjacent resilient members when the resilient members are in their unstressed or free state configuration.

Although min-or modifications might be suggested by those versed in the art, it should be understood that I wish to embody within the scope of the patent warranted hereon all such modifications as reasonably come within the scope of my contribution to the arts.

I claim as my invention:

1. In apparatus for winding and unwinding a traveling web, a core shaft mechanism for supporting the core comprising,

a shaft for receiving the core and adapted for rotation on an axis, and

a pair of clamping members co-rotatably mounted on said shaft and adapted to drivingly engage the core at opposite ends thereof,

at least one of said clamping members comprising a holding member having means for non-rotatably engaging the core and having a bore extending therethrough for slidingly receiving the shaft, means defining an annular recess in said holding member opening to said bore, and an annular resilient member housed in said recess and having a free state configuration to fit loosely around the peripheral wall of said shaft, said recess defined in part by a wall member adjustably movable with respect to said holding 5 member to vary the effective volume of said recess to alternately press said resilient member into a pressed state configuration to tightly grippingly engage the walls of said recess and the peripheral wall of said shaft to connect said holding member and said shaft in fixed assembly and to release said resilient member to its free state configuration to enable relative axial and rotational movement between said holding member and said shaft.

2. The apparatus as defined in claim 1 and including biasing means engaging said resilient member and urging said member out of gripping engagement with the peripheral wall of said shaft.

3. In apparatus for winding and unwinding a traveling web, a core shaft mechanism for supporting the core comprising,

a shaft for receiving the core and adapted for rotation on an axis, and

a pair of clamping members co-rotatably mounted on said shaft and adapted to drivingly engage the core at opposite ends thereof,

at least one of said clamping members comprising a holding member having means for non-rotatably engaging the core and having a bore extending therethrough for slidingly receiving said shaft,

means defining an annular recess in said holding member opening radially inwardly to said bore,

an annular resilient member housed in said recess and having a free state configuration to fit relatively loosely around the peripheral wall of said shaft, and adjustable means mounted on said holding member and extending into said recess to alternately axially squeeze said resilient member to force said member radially into tight gripping engagement with said holding member and the peripheral wall of said shaft to connect the holding member and said shaft in fixed assembly and to release said resilient member to its free state configuration to enable relative axial and rotational movement between said holding member and said shaft.

4. In apparatus for winding and unwinding a traveling web on and from a hollow core mounted on a rotatable 50 shaft, a core shaft mechanism for co-rotatably interconnecting the core and the shaft comprising,

a pair of axially spaced clamping members mounted on the shaft for connecting the shaft and the core in fixed assembly,

at least one of said clamping members comprising a holding member axially slidably carried on the shaft and having means for co-rotatably engaging the core and having an annular recess formed therein opening to the peripheral wall of the shaft,

an annular resilient member housed in said recess and wrapped relatively loosely around the peripheral wall of said shaft to provide relative axial and rotational movement between said holding member and the shaft, and

means mounted on said holding member and extending into said recess and selectively adjusttable to squeeze said resilient member and to load said resilient member in a radial direction to tightly grippingly engage the holding member and the peripheral wall of the shaft to'interconnect the holding member and the shaft in fixed assembly.

5. Apparatus for securing mounting a hollow core on 75 a rotatable shaft comprising,

a pair of axially spaced clamping members mounted on the shaft for connecting the shaft and the core in fixed assembly,

at least one of said clamping members comprising a holding member axially slidably carried on the shaft and having means for corotatably engaging the core and having an annular recess formed therein opening to the peripheral wall of the shaft,

an annular resilient member housed in said recess and wrapped relatively loosely around the peripheral wall of said shaft to provide relative axial and rotational movement between said holding member and the shaft,

means mounted on said holding member and extending into said recess and selectively adjustable to squeeze said resilient member and to load said resilient member in a radial direction to tightly grippingly engage the holding member and the peripheral wall of the shaft to interconnect the holding member and the shaft in fixed assembly, and

biasing means in said recess and engageable with said resilient member to urge said resilient member radially outwardly away from the peripheral wall of said shaft.

6. Apparatus for securely mounting a hollow core on a rotatable shaft comprising,

a pair of axially spaced clamping members mounted on the shaft for connecting the shaft and the core in fixed assembly,

at least one of said clamping members comprising a holding member axially slidably carried on the shaft and having means for frictionally engaging one end of the core to effect co-rotation between said holding member and the core,

means defining an axially extending recess in said holding member opening to the peripheral wall of the shaft,

a plurality of annular resilient members in said recess having a surface thereof confronting the peripheral wall of the shaft,

an insert slidably mounted on the shaft and having an axially facing shoulder extending into said recess and engageable with a resilient member, and

an adjustable locking member on said holding member engageable with said insert to selectively move said shoulder axially into pressing engagement with said resilient members to load the confronting surfaces of the resilient members radially into firm gripping engagement with the peripheral wall of the shaft to connect the holding member and the shaft in fixed assembly, and

biasing means in said recess and engageable with said resilient member to urge said members radially outwardly out of gripping engagement with said holding member and the shaft.

7. Apparatus for securely mounting a hollow core on a rotatable shaft comprising,

a pair of axially spaced clamping members mounted on the shaft for connecting the shaft and the core in fixed assembly,

at least one of said clamping members comprising a holding member axially slidably carried on the shaft and having means for frictionally engaging an end of the core to effect co-rotation between said holding member and the core,

means defining an axially extending recess in said holding member opening to the peripheral wall of the shaft and being generally rectangularly shaped in longitudinal cross-section,

a plurality of axially spaced annular resilient members situated in side-by-side relation in said recess,

each of said resilient members being generally circularly shaped in longitudinal cross-section and each having a surface thereof confronting the peripheral wall of the shaft,

an insert slidably mounted on the shaft and having an axially facing shoulder extending into said recess and engageable with a resilient memher,

an adjustable locking member on said holding member engageable with said insert to selectively move said shoulder axially into pressing engagement with said resilient member to load the confronting surfaces of the resilient members radially into firm gripping engagement with the peripheral wall of the shaft to connect the holding member of the shaft in fixed assembly, and

a plurality of axially split spring members situated in said recess and engageable respectively with said resilient members to urge said resilient members radially outwardly out of gripping engagement with said holding member and the shaft.

8. Apparatus for securely mounting a hollow core on a rotatable shaft comprising,

a holding member having a bore formed therethrough for slidably receiving the shaft,

said holding member having a surface formed thereon for frictionally engaging the core to provide fixed assembly of the holding member and the core,

means defining an annular recess in said holding member opening to said bore and to the peripheral wall of the shaft,

an annular resilient member housed in said recess extending substantially around the peripheral wall of the shaft,

said resilient member having a free state configuration providing an inner diameter enabling the resilient member and the shaft to move axially and rotattionally with respect to one another, and

adjustable means on said holding member to selectively impart an axial force on said resilient member to load the resilient member radially into firm gripping engagement with said holding member and the peripheral wall of the shaft to connect the holding member and the shaft in fixed assembly, and

spring means housed in said recess and engageable with said resilient member to urge said resilient member radially outwardly out of gripping engagement with said holding member and the shaft.

9. The apparatus as defined in claim 8 in which said resilient member is generally circular in longitudinal crosssection and said spring means constitutes an axially split spring.

10. The apparatus as defined in claim 9 in which said resilient member is circumferentially continuous.

11. The apparatus as defined in claim 9 in which said resilient member is axially split and in which an axially split spring is embedded in the resilient member.

12. In a paper making machine, apparatus for winding and unwinding a traveling paper web on and from a hollow core mounted on a rotatable shaft of a wind up reel comprising, a clamping member for releasably fixedly connecting the core and the shaft comprising,

a holding member slidably mounted on the shaft and having a shoulder surface formed thereon for frictionally engaging the core,

means defining an annular recess in said holding member opening to the peripheral surface of the shaft and comprising a pair of radially extending walls movable axially with respect to one another and an axially extending wall spaced radially outwardly from the shaft,

a plurality of annularly shaped resilient members positioned in a side-by-side relation in said recess and engageable with the walls of the recess and each having a confronting surface facing the peripheral wall of the shaft,

a plurality of annularly shaped axially split spring members in said recess and positioned respectively between the resilient members and between the resilient members and the radially extending Walls and engageable with the confronting surfaces of the resilient members to urge them radially outwardly out of engagement with the peripheral wall of the shaft, and

an adjustable means mounted on said holding member to selectively squeeze said radially extending walls into engagement with said resilient members to load the members radially into gripping engagement with said holding member and the shaft.

13. The apparatus as defined in claim 12 in which said resilient members and said spring members are generally circularly shaped in cross-section and wherein the ratio between the cross-sectional diameters of the resilient members and the spring members is in the range of from 6 to l to 2 to 1.

14. The apparatus as defined in claim 12 in which said radially extending walls of said recess are chamfered at their radially innermost ends to receive respectively an adjacent spring member.

15. In a paper handling machine, apparatus for winding and unwinding a traveling web on and from a windup reel comprising,

a shaft,

means rotatably mounting said shaft,

a hollow core for winding and unwinding the web thereon slidably carried on said shaft,

a guide roll in the path of the Web and engageable therewith to guide the web with respect to said core from or to associated rolls such as the rolls of a calender stack,

means to rotate said shaft, and

a core shaft mechanism for selectively positioning the core on said shaft in axial alignment with said guide roll and for releasably locking the core to the shaft for co-rotation therewith,

said core shaft mechanism comprising a pair of clamping members mounted on said shaft at opposite ends of said core,

each of said clamping members comprising an annular holding member slidably carried on the shaft and having means for co-rotatably engaging the core, and

locking means releasably locking said holding member to said shaft preventing axial and rotational movement relative to said shaft so that the core is maintained during rotation thereof in a positive position on said shaft with respect to said shaft and to said guide roll.

16. A core shaft clamping member comprising,

a holding member having means adapted to non-rotatably engage a shaft mounted core and having a bore extending therethrough for slidingly receiving the shaft,

means defining an annular recess in said holding member opening to said bore, and

an annular resilient member housed in said recess and having a free state configuration to fit loosely around the peripheral wall of the shaft,

said recess defined in part by a wall member adjustably movable with respect to said holding member to vary the effective volume of said recess to alternately press said resilient member into a pressed state configuration to tightly grippingly engage the walls of said recess and the peripheral wall of the shaft to connect the holding member to the shaft in fixed assembly then to release said resilient member to its free state configuration to enable relative axial and rotational movement between said holding member and the shaft.

References Cited by the Examiner UNITED STATES PATENTS 4/1949 Riesenfeld 24268 7/1961 Craig 242--68.2 

1. IN APPARATUS FOR WINDING AND UNWINDING A TRAVELING WEB, A CORE SHAFT MECHANISM FOR SUPPORTING THE CORE COMPRISING, A SHAFT FOR RECEIVING THE CORE AND ADAPTED FOR ROTATION ON AN AXIS, AND A PAIR OF CLAMPING MEMBERS CO-ROTATABLY MOUNTED ON SAID SHAFT AND ADAPTED TO DRIVINGLY ENGAGE THE CORE AT OPPOSITE ENDS THEREOF, AT LEAST ONE OF SAID CLAMPING MEMBERS COMPRISING A HOLDING MEMBER HAVING MEANS FOR NON-ROTATABLY ENGAGING THE CORE AND HAVING A BORE EXTENDING THERETHROUGH FOR SLIDINGLY RECEIVING THE SHAFT, MEANS DEFINING AN ANNULAR RECESS IN SAID HOLDING MEMBER OPENING TO SAID BORE, AND AN ANNULAR RESILIENT MEMBER HOUSED IN SAID RECESS AND HAVING A FREE STATE CONFIGURATION TO FIT LOOSELY AROUND THE PERIPHERAL WALL OF SAID SHAFT, SAID RECESS DEFINED IN PART BY A WALL MEMBER ADJUSTABLY MOVABLE WITH RESPECT TO SAID HOLDING MEMBER TO VARY THE EFFECTIVE VOLUME OF SAID RECESS TO ALTERNATELY PRESS SAID RESILIENT MEMBER INTO A PRESSED STATE CONFIGURATION TO TIGHTLY GRIPPINGLY ENGAGE THE WALLS OF SAID RECESS AND THE PERIPHERAL WALL OF SAID SHAFT TO CONNECT SAID HOLDING MEMBER AND SAID SHAFT IN FIXED ASSEMBLY AND TO RELEASE SAID RESILIENT MEMBER TO ITS FREE STATE CONFIGURATION TO ENABLE RELATIVE AXIAL AND ROTATIONAL MOVEMENT BETWEEN SAID HOLDING MEBER AND SAID SHAFT. 